64 



UNITED STATES AND MEXICAN BOUNDARY. 



4. TIGOMA GIBBOSA, Grd, 

 Plate XXXIII, Figs. 1—4. 



Spec. Char.— Body rather thick ; dorsal region between dorsal fin and occiput more arched than generally observed in this 

 genus. Head forming a little less than the fourth of the entire length ; greatest depth nearly equal to the length of head . 

 Eyes quite large ; their diameter contained five times in the length of the side of head. Anterior margin and dorsal fin nearer 

 the base of caudal than the tip of snout. Ventrals, as usual, in advance of the dorsal, and anal behind the latter. Greatest 

 length of caudal fin constituting nearly the seventh of the entire length. 



Six.— Gila gibbosa, B. & G. in Proc. Acad. Nat. Sc. Philad. VII, 1854, 28. 



Tigoma gibbosa, Grd. in Prec. Acad. Nat. Sc. Philad. VIII, 1856, 207. 



The scales, irregularly sub-elliptical, are longer than deep, and exhibit radiating furrows 



upon their entire periphery. 



D 1, 8 + 1 ; A 1, 9 ; C 5, 1, 9, 8, 1, 4 ; V 9 ; P 17. 



Color in alcohol, dark reddish brown above and laterally ; dull yellow beneath. 



Plate XXXIII, fig. 1, represents Tigoma gibbosa, size of life ; fig. 2 being a scale from the 

 dorsal region ; fig. 3, a scale from the lateral line; and, fig. 4, a scale from the abdominal 



region. 



List of specimens. 



Catal. 



Cor. No. 



No. of 



No. 



of teeth. 



spec. 



223 



2776 



15 



222 



2775 



10 



Locality, 



Rio Santa Cruz, Mex 

 Tuscon, Sonora 



When 

 collected. 



1851 



Whence obtained 



Col. J. D. Graham. . 



Nature of 

 specimen. 



Alcoholic . 



Collected by- 



Jno. II. Clark 



Lt. J. G. Parke ....... .do. . • . Dr. A. L. Heermann 



5. TIGOMA NIGKESCENS, Grd. 



Plate XXXII, Figs. 1—4. 



This is quite an elegant species, being elongated and slender, like T. pulchella and T. gracilis. 

 It diifers from T. gibbosa by a more conical head and snout. The ground color is yellowish, 

 the middle of the scales being covered with crowded black dots, the back and sides appearing 

 almost black. The belly is unicolor. In the young the upper regions are lighter than in the 

 adult. 



Syn. — Tigoma nigrescent, Grd. in Proc. Acad. Nat. Sc. Philad. VIII, 1856, 207. 



Plate XXXII, fig. 1, represents Tigoma nigrescens, size of life ; fig. 2, a dorsal scale ; fig. 3, 

 a scale from the lateral line ; fig. 4, a scale from the abdominal region. 



List of specimens. 



Catal. 



No. 



Cor. No. 

 of teeth. 



No. of 

 spec. 



220 

 219 



2774 



10 



1 



Locality 



Boca Grande 



J an os river ...... ..... 



When col- 

 lected. 



1854 



Whence obtained 



Nature of 

 specimen. 



Maj. Emory Alcoholic . 



do 



do 



Collected by 



Dr. C. B. Kennerly- — 

 do 





